The Horse:Your Guide To Equine Health Care provides monthly equine health care information to horse owners, breeders, veterinarians, barn/farm managers, trainer/riding instructors, and others involved in the hands-on care of the horse.
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38 TheHorse.com THE HORSE October 2015 Y ou're headed out to catch your pastured horse for a riding lesson when you notice that his hock is the size of a softball. Later, you hold your breath as the veterinarian examines the injury and cringe at the sound of those two dreaded words: stall rest. Continu- ous confinement of any horse for long periods poses many obstacles, especially where nutrition is concerned. Diet plays a critical role in a horse's behavior and overall gastrointestinal health, and not implementing a proper feeding program for a horse on stall rest can be worse than the injury itself. Cutting the Calories Whether your patient is a racehorse or a weekend trail horse, stall rest means a serious reduction in his usual amount of activity—voluntary and otherwise. Depending on his level of work prior to the injury, you will need to reduce his total calorie intake to account for the decrease in activity. Here's an example of a 1,100-pound horse's daily caloric requirements: TABLE 1 Level of Work & Description Mcals per Day Idle: minimal activity 15.2 Light: recreational riding 20.0 Moderate: school horses, ranch work 23.0 Heavy: low-level eventing, show horses 26.6 Very Heavy: racing, endurance, elite three-day eventing 34.5 From NRC Nutrient Requirements of Horses, 2007 There are two main calorie sources in a horse's diet: carbohydrates and fats. Carbohydrates are further divided into two types: structural and nonstructural. Horses receive structural carbs from the fiber found in hay and pasture. The nonstructural carbs come mainly from cereal grains, such as oats, and include sugar and starch. Fats, such as vegetable oils, contain approximately 2.5 times the calories of carbohydrates and are made up of long chains of fatty acids. The horse needs all these calorie sources to produce adenosine triphosphate (ATP), the fuel that powers the body's systems, including the muscular and thermoregulatory systems, during physical activity. So the question is, what calories should you cut from the diet first during stall rest? To answer this, let's take a look at the anatomy of the horse's digestive system. The foregut is comprised of the stom- ach and small intestine. Enzymes in the stomach break down most of the fat and nonstructural carbohydrates, which the small intestine then absorbs. Stall rest restricts a horse's ability to forage—the act of seeking out and consuming small meals throughout the day. And horses that aren't able to partake in their daily graz- ing routine can be predisposed to gastric ulcers, says Anne Baskett, DVM, Dipl. ACVS, a surgeon with a special interest in sport horse medicine and lameness at Tryon Equine Hospital, in Columbus, North Carolina. Saliva, which is high in bicarbonate and only produced by the act of chewing food, helps to buffer the stom- ach's acidic secretions. Therefore, longer time between meals increases the horse's risk for gastric ulcer formation. The hindgut includes the cecum, large colon, small colon, and rectum and is the main site of fiber digestion. Within the cecum and colon reside billions of microbes charged with breaking down fiber into volatile fatty acids the body can use for ATP production. These microbes do not cope well with rapid changes to their daily routine or environment, such as times without adequate fiber, and health issues such as colic can result. In addition, researchers have found evidence that reduced or restricted locomotion can decrease a horse's gastrointestinal motility—the movement of food through the digestive tract. NUTRITION KRISTEN M. JANICKI, MS, PAS TheHorse.com/Nutrition Feeding Horses on Stall Rest Take steps to manage your horse's weight and behavior while he's cooped up Stalled horses need plenty of hay to ward off gastric ulcers and to keep their digestive tract moving. ISTOCK.COM